In forest management, having an accurate inventory of trees in a forest is important to be able to manage forest lands effectively. Forest managers use inventory data to determine when it is time to harvest trees in a forest as well as for determining the value of such trees depending on market conditions. In the past, survey crews would be sent into a forest to do statistical sampling of tree heights, species and diameters. From the samples collected, an estimate of timber volume and value can be determined. As the size of forests under active management increase and/or more remote areas are actively managed, it is becoming cost prohibitive and impractical to send crews into enough places in the forest to obtain good sample data. More recent technology for sampling involves the use of remotely obtained data such as aerial or satellite images. While remotely sensed images can be used to determine tree species and ages for tree stands (i.e. groups of homogenous trees), it is time consuming to get information about individual trees in a forest from remotely sensed images even if images with fine resolution provide such information.
A newer technology that can be used to remotely sample individual trees in a forest is Light Detection and Ranging (LiDAR). With LiDAR, an airplane, helicopter or other relatively low flying aircraft is used to direct laser pulses towards the ground in a repetitive sweeping pattern. The laser pulses are reflected off the trees, ground or other objects back to a detector on the aircraft. The time of receipt, direction and the intensity of each received pulse is recorded. Because the height and location of the aircraft are known, a three dimensional map of the forest land surveyed with the LiDAR system can be produced.
With LiDAR sampling, there is a lot of data available to be able to determine such information as tree heights and canopy widths. However, there is a need for a system and method of analyzing the LiDAR data to be able to identify additional characteristics about individual trees in the forest such as their species, approximate age, branch structure or other factors that are important in determining a value or other the information about the trees.